Francesco Ruggeri <frugg...@arista.com> writes:
> Resending, did not include netdev the first time ...
>
> If a macvlan/macvtap creation fails in register_netdevice in
> call_netdevice_notifiers(NETDEV_REGISTER) then while cleaning things up in
> rollback_registered_many it invokes macvlan_uninit. This results in
> port->count being decremented twice (in macvlan_uninit and in
> macvlan_common_newlink).
> A similar problem may exist in the ipvlan driver.
> This patch adds priv_flags to struct macvlan_dev and a flag that
> macvlan_uninit can use to determine if it is invoked in the context of a
> failed newlink.
> In macvtap_device_event(NETDEV_UNREGISTER) it also avoids cleaning up
> /dev/tapNN in case creation of the char device had previously failed.
> Tested in 3.18.
These interactions all seem a little bit funny. At a quick skim it
would make more sense to increment the port count in macvlan_init,
and completely remove the need to mess with port counts anywhere except
macvlan_init and macvlan_uninit.
If for some reason that can't be done the code can easily look at
dev->reg_state. If dev->reg_state == NETREG_UNITIALIZED it should
be exactly the same as your new flag being set.
> diff --git a/include/linux/if_macvlan.h b/include/linux/if_macvlan.h
> index a4ccc31..7cf82d8 100644
> --- a/include/linux/if_macvlan.h
> +++ b/include/linux/if_macvlan.h
> @@ -48,6 +48,7 @@ struct macvlan_dev {
> netdev_features_t set_features;
> enum macvlan_mode mode;
> u16 flags;
> + u16 priv_flags;
> /* This array tracks active taps. */
> struct macvtap_queue __rcu *taps[MAX_MACVTAP_QUEUES];
> /* This list tracks all taps (both enabled and disabled) */
> @@ -63,6 +64,8 @@ struct macvlan_dev {
> unsigned int macaddr_count;
> };
>
> +#define MACVLAN_PRIV_FLAG_REGISTERING 1
> +
> static inline void macvlan_count_rx(const struct macvlan_dev *vlan,
> unsigned int len, bool success,
> bool multicast)
